Staple strip and method of making same



A. D. TIB ALs Sept 10, 1929.

Filed March 31, 1922 Inv tor Patented Sept. 10, 1929.

ALBERT D. TIIBIBALS, ST. LOUIS, MISSOURI.

STAPLE STRIP AND METHOD OF MAKING SAME.

Application filed. March 31, 1922. Serial No. 548,395.

My invention relates to staples such as are used in fastening a plurality of sheets of stationery, cloth, or like material to each other and as are supplied ordinarily in strips of about twenty-five staples which are integrally united and adapted to be severed by the ma-.

chine which inserts them through the sheets of paper or other material and then clinches the points. I

Where heavy grades of paper are used or even a substantial number of sheets of thinner paper, the pressure necessary to force the points of the staples through the papers frequently doubles the points upon themselves before they have pierced the paper and the body of the staple may be distorted also because of its lack of rigidity.

One object of my invention is to shape the points of the staples so that they will more readily withstand the pressure used when the staple is inserted through material to be bound together. In so shaping the pointsof the staple I also desire to harden them by compacting the material by swaging or otherwise, thereby increasing the strength of the oints.

Another object of my invention is to make a staple which will be stiffened throughout its body by the provision of skeleton-like areas, hardened by compacting the metal, and of suitablereinforcing ribs.

The strips of staples now made are easily bent in handling so that difiiculty is often experienced in packing them, in inserting them in the machine, and in feeding them through the machine. An additional object of my invention is to stiffen the strip as a whole so that this objectionable feature will be overcome.

Another object of my invention is to obtain a more secure interengageme'nt of the staple and the material to which it is attached.

In the production of these staples I utilize several novel steps which enable me to make a staple strip with the above-mentioned improvements as economically as the strips previously manufactured. In an article of this type, which must be sold at a small price, the provision of efficient manufacturing methods is absolutely essential, and a further object of my invention is to provide manufacturing steps which will enable me to produce strips of staples having the improvements referred to without increasing their cost.

In the accompanying drawings, which illustrate my strip and the various steps in the manufacture of the same,

Figure 1 is a View of a portion of a metal sheet from which the staple strips are stamped and indicating the first and suc-. ceeding stampings.

Figure 2 is a top view of a single staple strip blank stamped from the sheet shown in Figure 1.

Figure 3 is a fragmentary top View, on an enlarged scale, of a completed staple strip. Figures 4 and 5 are sections taken on lines 4-& and 5-5, respectively, of Figure 3; Figure 4: showing in part the swaging dies;

Figure 6 is a side view of the strip shown in Figure 3.

Figure 7 is a detail showing the action of my improved staple when attached to sheets of paper or the like.

It will be understood that the stamping of these strips is a punch-press operation, and that the stock 1 from which the strips are stamped is supplied in rolls, the width of which is approximately the same as the length of one of the staple strips to be produced. When a roll is started through the press, the preliminary cut 2 is taken to stamp the first series of serrations across the end of the stock. Thereafter each operation of the press stamps a pair of serrated cuts as 3 and 4, leaving a continuous strip of metal 5 across the stock. Each of the cuts stamps all of the serrations on the adjacent sides of two successive staple strips. By stamping two cuts, as 3 and 4, simultaneously the punch knives are bale anced and more easily maintained in alignment.

Each of the blanks stamped from stock 1 is of the shape indicated in Figure 2.. These are fed to a forming press where they are given the transverse U-shape shown in Figures 4 and 5 and simultaneously are provided with a longitudinal indentation 6 and. transverse indentations and ribs 7 and 8, the longitudinal indentation 6 being common to all or" the staples and the transverse ribs 7 and 8 being provided for each individual staple. The forming of these indentations and ribs hardens the metal by compacting and rein forcing it so as to stiffen the strip throughout its length and the individual staples throughout their respective lengths so that the strip and the staples possess sufficient rigidity for their handling both in and out of a stapling machine.

Simultaneous with the formation of the indentations and ribs, the alinged tapered points 12 of the legs of the staples are swaged simultaneously, as indicated in Figure 4, by the hammers 9 slidably mounted on the die blocks 10 and 11, whereby the points on the staple le s are compressed and flattened to change the rounded terminals 12 shown in Figure 2 to the chisel-like terminals 13 shown in Figure 6. This compression not only forms a chisel-like edge for the end of the staple but by compressing the metal so hardens it that even if the original shape had been retained, a greater resistance would be imparted to the piercing portion of the staple. The chisel-like edge, however, cuts through the stapled material more eflectively than the thick point now produced on similar staples and retains the stiffening advantage of a long narrow surface rather than a point surface. It also reduces the burr usually resulting from a pointed perforating element.

Another advantage of this type of edge is indicated in Figure 7 which shows a single staple from the strip after being clinched in a stapling machine. The initial pressure of the machine anvil on the edges 13 causes the latter to curl before the bending of the remainder of theleg, and in the curling of the terminal, the adjacent paper or cloth is gripped more securely than by the ordinary staple, the legs of which are merely doubled on themselves or the staple body.

It will be noted that the original rounded terminals of the staple legs provide a space 14 between each leg in which the minimum width of strip 5 is practically maintained for a suflicient distance to make unobjectionable a slight variation in the positioning of the staple strips in a staple severing and setting machine. In other words, the length of a cut to be made by the machine blade will be increased only a trifle by such shifting of the staple strip in the machine as is likely to result from different lengths of the strips due to allowable variations in the width of the stock 1 and other manufacturing inequalities. This is an advantage over strips having V-shaped recesses between the staples and which must be severed precisely at the apex of the recess or abnormal pressure will be required to sever the staple.

Ihe staples just described may be formed as cheaply as those now on the market and possess the previouly mentioned advantages of being stiffer and having greater penetrating power without any increase in the amount of material used.

I am aware that various modifications in the exact details of the staples and strips may be adopted without departing from the spirit of my invention as expressed in the following claims.

I claim:

1. In a staple strip, a plurality of united staples disposed transversely of the strip, a continuous indentation forming a compressed area extending longitudinally of the strip and tranversely of the staples, and a plurality of corrugations extending transversely of the body of the strip and longitudinally of the respective staples.

2. The method of making a staple strip which includesthe bending of a strip into a U-shaped cross section and the simultaneous swaging of stifiening indentations longitudinally and transversly of the strip.

3. The step in the manufacture of staple strips which includes the swaging of indentations in the body of the strip and individual ribs in each staple to harden the metal and stiflen the strip as a whole and each staple individually and simultaneously swaging chisel-shaped terminals on each staple individually.

4. In a staple strip, a plurality of U- shaped staples arranged transversely of the strip, each provided with compressed portions extending along the longitudinal line of the staple and around the angles of the v staple.

5. A staple strip reinforced throughout its length and comprising a plurality of staples each reinforced individually through out its length by means of swaged indentations.

6. In a staple strip, a plurality of U- shaped staples arranged transversely of the strip, each having reinforcing ribs extending longitudinally of the horizontal and V81" tical portions of the staple and spaced from each other at the center of the strip.

7. The method of forming a staple strip which consists in producing a blank with a series of pairs of oppositely extending teeth, forming said blank over three sides of a die member to give each pair of teeth a U-shape,

and swaging the ends of the teeth against said member. Y

8. The method of forming a staple strip which consists in producing a blank with a series of pairs of oppositely extending teeth, forming said blank over three sides of a die member to give each pair of teeth a U-shape, and simultaneously swaging the ends of all the teeth against the opposite sides of said member.

In testimony whereof I hereunto aflix my signature this 16th day of March, 1922;

ALBERT D. TIBBALS. 

